TM> easily solved by putting %1 etc in the correct spot in the alias.
  > That's why I mentioned aliases in the first place.

 I don't think I started following it that far back.  I came in at

TM> Try `Set .ext=Edit %1 something_else`

 which spoke nought of aliases.

TM> to get the %1 parameter in place, you may need back-quotes

 I never do for-keeps aliases from the command line, but was
 doing them that way as tests during the message, and probably
 did leave out the back-quotes.

TM> The %1 parameter was meant for use in an alias, so that
  > one might alter the appearance or the order of parameters.

 It's the backstory I was missing.  Your 98-11-19 message said
 nothing of aliases, nor did Didier's 98-11-07 to which you were
 replying, nor did your 98-11-04 to which he was replying, and
 that's as far back as the board's message base goes today.  No
 doubt they were mentioned somewhere in the conversation, but by
 the time I saw something that looked interesting and tried it,
 the important bit wasn't being mentioned any more.

TM> I would like to hear from you again, telling
  > me whether or not it works as expected.

 Yes, once it's clear that an alias is required, and not simply
 an ExecExt as you seemed to be saying, it does work.  For the
 archiver RKIVE, for example, which won't even list contents
 unless you spell it all out: "rkive -v whatever.rkv *.*".
 So having an ExecExt of ".RKV=rkv_" and an alias of
 "rkv_=vv rkive -v %1 *.*" (where vv=%&|list/s) lets RKVs join
 the other archive-listing ExecExts like ".J=vv jar l" and
".ZIP=av"
 (where av=AinView, an archive viewer which can't handle JARs,
 RKVs, HPKs and a few other varieties I occasionally see/use).

... An error gracefully acknowledged is a victory won. * Gascoigne
--- SR 2.00 #1019